1. Field of the Invention
The present invention relates to the art of electrical connectors, and more particularly to a cable assembly having conductive wires extending through a longitudinal side wall of a shielding of an electrical connector thereby providing a low profile, the cable assembly providing EMI (Electro Magnetic Interference) protection to ensure reliable high-speed signal transmission.
2. Related Art
A cable assembly is commonly used to electrical interconnect two separate electrical systems. The cable assembly typically includes a cable and two cable end connectors respectively connected to ends of the cable. The cable can be a coaxial cable, a flat cable or a multi-wire cable, any of which electrically connects to electrical terminals of the cable end connectors by any of several commonly used connecting technologies. Such technologies include soldering, crimping, and IDC (Insulation Displacement Contact) technology.
With the popularization of portable electronic devices such as notebook computers, a cable assembly used to transmit signals in such devices is required to have a minimized cable diameter as well as a low profile configuration for at least one of the cable end connectors. That way, the cable assembly does not occupy too much space within the portable device. Further, with the development of high-speed signal transmission technology, the cable assembly needs to reliably transmit high-speed signals. A metallic shielding is commonly required to be attached to the cable assembly, in order to prevent EMI (Electro Magnetic Interference) in relation to the external environment. The metallic shielding is often called an EMI shielding.
Attaching an EMI shielding onto an insulative housing of a cable end connector has been widely practiced in the art, and pertinent examples of such structures are disclosed in U.S. Pat. Nos. 6,162,086 and 6,179,662. However, these structures have shortcomings; that is, either not satisfactorily meeting the requirement of ensuring high-speed signal transmission, or not satisfactorily meeting the requirement of having a low profile configuration for the cable end connector.
U.S. Pat. No. 6,162,086 discloses a cable assembly having an outer EMI shielding. The cable is received into the housing of the connector from a top wall of the connector. When the connector is mounted to a substrate, an overall height of the connector and substrate is increased. The high configuration of the connector occupies a good deal of valuable space. Therefore, it is difficult to use the connector in a compact electronic device.
U.S. Pat. No. 6,179,662 discloses another kind of cable assembly. The cable is received into the housing of the connector from a first transverse end wall of a connector body. Therefore, the overall height of the cable assembly is less than that disclosed in U.S. Pat. No. 6,162,086. However, the cable assembly has disadvantages that reduce high-speed signal transmission performance. Each terminal in the connector body is connected with a corresponding signal wire of the cable. Some of the signal wires extend all the way through to an opposite second transverse end wall of the connector body, while other signal wires only extend a little beyond the first transverse end wall of the connector body. That is some of the signal wires are substantially longer than other signal wires. The difference between the lengths of these two types of signal wires is substantially along a length of the connector body. When the cable transmits high-speed signals, the difference in lengths of the signal wires impairs the synchronicity and accuracy of signal transmission.
Therefore, what is needed is a new low profile cable assembly that overcomes the above-described shortcomings.
An object of the present invention is to provide a cable assembly having an EMI shielding which maintains a low-profile configuration for the cable assembly as well as yielding excellent EMI performance.
Another object of the present invention is to provide a metallic shielding for a low profile cable end connector, the shielding being easily attached to the connector and yielding reliable EMI protection throughout the connector and an associated cable.
To fulfill the above objects, a cable assembly in accordance with the present invention comprises an insulative housing having a plurality of electrical terminals received therein. The housing has a mating surface adapted to mating with a mating header connector. A metallic shielding, which comprises a first portion and a mating second portion, is attached to the housing, the shielding functions as an EMI device. The shielding substantially surrounds the housing, and has a first opening in alignment with the mating surface of the housing and a second opening formed near a middle portion of one longitudinal side wall of the shielding. Conductive wires of a cable extend through the second opening and establish electrical connection with the terminals in the housing.
An adapter, which is made of conductive material and is partially received in the shielding, comprises a base retained between the first and second portions of the shielding and a cylindrical connecting portion extending out of the shielding from the second opening in the side wall of the shielding. An inner channel is defined throughout the adapter such that the conductive wires of the cable can extend through the adapter and enter the shielding, and inner wall of the channel contacts with an EMI shielding in the cable. The shielding, the adapter and the EMI shielding of the cable cooperatively provide overall EMI protection throughout the cable assembly, and the adapter can also reinforce the strength of the cable assembly.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.